WBest: a Bandwidth Estimation Tool for Multimedia Streaming Application over IEEE 802.11 Wireless Networks

Multimedia streaming applications can benefit from bandwidth estimation techniques to perform media scaling and buffer optimization efficiently. However, most current techniques were designed fo r wired networks and produce relatively inaccurate results and long co nvergence times on wireless networks where capacity and contention for the c apacity can vary dramatically. Therefore, it is difficult to apply curre nt bandwidth estimation tools to multimedia streaming applications in wireless network. This paper presents a new Wireless Bandwidth estimation too l (WBest) designed for fast, non-intrusive, accurate estimation of ava ilable bandwidth in IEEE 802.11 networks. WBest applies a two-step algorithm: 1) a packet pair technique to estimate the effective capacity of the wir eless networks; 2) a packet train technique to estimate the achievable through put and report the inferred available bandwidth. Using an analytic model,the possible error sources are explored and WBest parameters are optimizedgiven the tradeoffs of accuracy, intrusiveness and convergence time . The advantage of WBest is that it does not depend upon search algorithms to d etect the available bandwidth but instead, statistically detects the available fraction of the effective capacity, mitigating estimation delay andthe impact of random wireless channel errors. WBest is implemented and evalu ated on an 802.11 wireless testbed. Comparing WBest with other popula r bandwidth estimation tools shows WBest to have higher accuracy, lower intrusiveness and faster convergence times. Thus, WBest demonstrates the potential for improving the performance of applications that need bandwi dth estimation, such as multimedia streaming, on wireless networks.